Implement Project 2: Arithmetic Logic Unit

✅ HalfAdder: XOR for sum, AND for carry
✅ FullAdder: Two half adders + OR
✅ Add16: Chain of 16 full adders with carry
✅ Inc16: Add16 with constant 1
✅ ALU: Complete arithmetic logic unit with all operations

Used concise, student-style comments throughout.

02/Inc16.hdl

@@ -11,5 +11,6 @@ CHIP Inc16 {
     OUT out[16];
 
     PARTS:
-    //// Replace this comment with your code.
-}
+    // Add 1 using Add16
+    Add16(a=in, b[0]=true, b[1..15]=false, out=out);
+}